KR20210144817A - Blood pressure measuring device and method therefor - Google Patents

Abstract

[Project] To provide an apparatus for measuring blood pressure by non-invasive lipid measurement.
[Solution Means] An irradiating unit irradiating light having periodicity to a subject having a first layer on its surface and a second layer absorbing more light than the first layer below the first layer, and the light having periodicity is emitted from the irradiating unit a light intensity detector that is disposed at a distance to be detected as light having lost periodicity through the first and second layers, and detecting the intensity of light having lost periodicity emitted from the subject; and a control unit for calculating blood pressure in the subject.

Description

Blood pressure measuring device and method therefor

The present invention relates to an apparatus and method for measuring blood pressure.

In the conventional biometrics using light, in order to utilize two phenomena of absorption and scattering, various studies have been conducted in the analysis.

For example, Patent Document 1 proposes a method of deriving a scattering coefficient and an absorption coefficient by one measurement.

WO 2014087825 A

However, in this method, since it is the premise that the subject is a homogeneous layer, it is necessary to further improve the precision in the biometric measurement comprising a plurality of layers. In addition, there is a possibility that blood pressure can be measured if the precision of biometric measurement is improved.

The present invention is an invention made in order to solve such a conventional problem, and is to provide an apparatus and method for measuring blood pressure by non-invasive lipid measurement.

The blood pressure measuring device of the present invention comprises: an irradiator for irradiating light having periodicity to a subject having a first layer on the surface and a second layer absorbing light more than the first layer below the first layer; a light intensity detection unit configured to detect the intensity of the light having lost periodicity emitted from the subject, the light intensity detecting unit being disposed at a distance where light having passed through the first layer and the second layer has lost periodicity, and is disposed at a detection distance; and a control unit for calculating blood pressure in the subject from the intensity of one light.

The blood pressure measuring device of the present invention comprises: an irradiator for irradiating light having periodicity to a subject having a first layer on the surface and a second layer absorbing light more than the first layer below the first layer; A user device comprising: a light intensity detector configured to detect the intensity of light having lost periodicity emitted from the subject by being disposed at a distance at which light having lost periodicity passing through the first and second layers is detected A blood pressure measuring apparatus comprising: a control unit communicatively connected to the to-be-tested body and calculating the blood pressure in the subject from the intensity of light having lost periodicity transmitted from the user device.

Further, in the blood pressure measuring method of the present invention, a subject having a first layer on its surface and a second layer that absorbs light more than the first layer below the first layer is irradiated with light having a periodicity, At a position where light having periodicity passes through the first layer and the second layer and becomes light losing periodicity and is detected, the intensity of light having lost periodicity emitted from the subject is detected, and from the intensity of light having lost periodicity The blood pressure in the subject is calculated.

According to the blood pressure measuring apparatus and method of the present invention, it becomes possible to measure blood pressure.

1 is a diagram showing the periodicity of light.
Fig. 2 is a diagram showing the disturbance of the periodicity of light.
3 is a diagram illustrating a two-layer system.
4 is a diagram illustrating a correlation between wave height and blood pressure.
Fig. 5 is a diagram showing a configuration example of the blood pressure measuring device according to the embodiment.
6A is a view showing an example in which the light intensity detection unit is disposed on the face.
6B is a view showing an example in which the light intensity detection unit is disposed on the face.
Fig. 7 is a block diagram of the blood pressure measuring device according to the embodiment.
Fig. 8 is a diagram showing a configuration example of a blood pressure measuring device according to another embodiment.
Fig. 9 is a flowchart of the blood pressure measuring method according to the embodiment.

First, the blood pressure measuring device of the embodiment and the measurement principle of the method will be described.

As shown in Fig. 1, light having a periodicity like a fluorescent lamp emits light with periodicity, and a change in received light intensity follows it.

When light having periodicity is incident on the scattering absorber, the periodicity is lost as shown in FIG. Here, the difference (C in the drawing) between the maximum value (A in the drawing) and the minimum value (B in the drawing) of the received light intensity within a predetermined time of the incident light is referred to as a wave height. Although this periodicity seems to be disordered at a glance, even if the periodicity seems to have disappeared, the photons with the least absorption effect by the absorption scattering body show the maximum and minimum values, and the photons lost by absorption appear in a disordered state.

This phenomenon can be applied to, for example, the two-layer system shown in FIG. 3 consisting of a scattering body thin film layer (first layer) and an absorption scattering body (second layer) below it. In the case of the two layers having different refractive indices, the incident light X is diffused to the first layer, so that the amount of light incident on the second layer is reduced.

That is, in the light receiving unit A, light not being absorbed only by scattering and two types of light affected by scattering absorption are received.

In actual measurement, it is also possible to replace the first layer with the epidermis and the second layer with the dermis layer, and a layer containing blood and a layer not containing blood by a capillary layer or the like.

When the distance between the incident portion and the light-receiving portion is relatively short as in the light-receiving portion A, it is affected by the absorption of light by the absorption scattering body due to the disturbance of the waveform, the decrease in the wave height and the measured value. Since the wave height analysis at this distance includes absorption and reflection at an acute angle to the back, it is assumed that the influence of blood cells, which are absorption scatterers larger than the wavelength, is greater.

Therefore, the present inventor verified the correlation between the wave height (difference in the measured values of the light reception intensity (C) in FIG. 2) and blood pressure when the distance between the incident part and the light receiving part is relatively short as in the light receiving part (A) of FIG. This is because the blood pressure assumes the maximum blood pressure and indirectly expands the capillaries, so that it is considered that the blood ratio of the optical path is increasing.

The short distance between the incident portion and the light-receiving portion as used herein is a region in which the period of incident light is lost and detected. For example, the distance between the incident portion and the light-receiving portion is a distance that cannot be confirmed by whether or not an intensity of 1/20 or more is obtained with respect to the incident light intensity in terms of light reception intensity, or the period of light is lost by FFT analysis. For example, the determination of periodicity of light confirmed by FFT analysis can be judged to have periodicity when it is larger than 1.1 times the intensity value of 10 Hz before and after the target frequency by FFT analysis (that is, measurable FFT) Intensity ratio>(intensity in FFT of target frequency)/{[(intensity in FFT of target frequency + 10 Hz) + (intensity in FFT of target frequency - 10 Hz)]/2}=1.1)). Conversely, in the judgment of the periodicity of light confirmed by the FFT analysis, it can be judged that the periodicity is lost when the intensity value of 10 Hz before and after the target frequency is 1.1 times or less by the FFT analysis.

4 shows the correlation between wave height and blood pressure. As shown in the figure, light measurement and blood pressure measurement were performed for 6 subjects 6 times a day. As a result, the correlation was 0.7 or more, and it was confirmed that blood pressure could be measured.

In addition, although the wave height can be measured in the case of a wave height of only one point, a measurement error tends to occur because absorption and scattering are included. Therefore, it is desirable to smooth out the error during measurement because of the rate of change of the crest strength when light is received at a plurality of points at the same distance or when the distance is changed.

In addition, the amplitude of the wave height may be known, and may be the median or average value of the measured values of the wave height within the measurement time, and the width of the maximum value or the minimum value. In addition, the difference between the average value of the measured values of the wave height and the peak top, or the difference between the average value of the measured values of the wave height and the peak bottom, that is, the half value may be analyzed.

EMBODIMENT OF THE INVENTION Below, embodiment is described using drawing.

Fig. 5 is a diagram schematically showing a configuration example of the blood pressure measuring device 100 according to the embodiment. As shown in FIG. 5 , the blood pressure measuring apparatus 100 includes an irradiation unit 11 , a light intensity detection unit 12 , and a control unit 13 .

The irradiation unit 11 of the embodiment is disposed with a predetermined distance rho from the light intensity detection unit 12 . The irradiation unit 11 irradiates light having periodicity to the subject C having a first layer on the surface and a second layer that absorbs light more than the first layer below the first layer. The irradiation part 11 is a fluorescent lamp, LED, a laser, an incandescent lamp, HID, a halogen lamp, etc., for example. In addition, the illumination part 11 may adjust the light-shielding time by providing mechanisms, such as a shutter which is periodically opened and closed, and may give periodicity to the irradiated light continuously irradiated. The illuminance of the irradiation unit 11 is controlled by the control unit 13 .

The irradiator 11 can adjust the wavelength range outside of the wavelength range where light is absorbed by inorganic substances in plasma. The irradiation unit 11 can be adjusted outside the wavelength range in which light is absorbed by the cellular components of blood. Here, the cellular components of blood are red blood cells, white blood cells, and platelets in blood. The inorganic substances in plasma are water and electrolytes in the blood.

In the embodiment, the blood measurement device 100 includes the irradiation unit 11, which is a light source having periodicity. do. In this case, it is unnecessary to provide the irradiation unit 11 in the blood measurement device 100 .

The light intensity detection unit 12 of the embodiment receives light emitted from the inside of the subject C to the outside of the subject C. The light intensity detection unit 12 is disposed at a distance ρ from the irradiation unit 11 at which the light having periodicity passes through the first layer and the second layer of the subject C and becomes light having lost the periodicity and is detected. do. The light intensity detection unit 12 of the embodiment is a photodiode. The light intensity detection unit 12 is not limited to a photodiode, and may be a CCD or CMOS. The light intensity detection unit 12 detects the intensity of light that has lost periodicity emitted from the subject. The light intensity detection unit 12 may set a wavelength other than visible light, and may be capable of receiving the wavelength. The light intensity detection unit 12 is controlled by the control unit 14 . The light intensity detection unit 12 transmits the detected light intensity to the control unit 14 .

6A and 6B , the light intensity detection unit 12 (light receiving unit in the drawing) may be disposed opposite to the irradiation unit 11 sandwiching the subject. Such an arrangement is also possible when measuring a place that has relatively little thickness and where light easily penetrates, such as an earlobe or fingertip. The irradiation unit and the light intensity detection unit (the light receiving unit in the drawing) may or may not contact the subject ( FIG. 6B ) or may not contact them ( FIG. 6A ).

Next, the configuration of the control system of the blood pressure measuring device 100 will be described. Fig. 7 is a block diagram of the blood pressure measuring device 100 according to the embodiment. Through the system bus 132, CPU (Central Processing Unit) 131, ROM (Read Only Memory) 133, RAM (Random Access Memory) 134, HDD (Hard Disk Drive) 135, external An I/F (Interface) 136 , an irradiation unit 11 , and a light intensity detection unit 12 are connected. The control unit 13 is constituted by the CPU 131 , the ROM 133 , and the RAM 134 .

The ROM 133 stores in advance a program to be executed by the CPU 131 and a threshold value.

The RAM 134 has an area in which a program executed by the CPU 131 is developed, and various memory areas such as a work area serving as a work area for data processing by the program.

The HDD 135 stores data in which the correlation between blood pressure and wave height is created for a plurality of persons as a calibration curve.

The external I/F 136 is, for example, an interface for communicating with an external device such as a client terminal (PC). The external I/F 136 may be an interface for data communication with an external device, for example, may be a device (USB memory, etc.) connected locally to the external device, or may be a network interface for communicating via a network. do.

In the blood pressure measurement apparatus 100 having the above configuration, the blood pressure measurement apparatus 100 executes a blood pressure measurement job based on a preset program.

The control part 13 calculates a wave height from the intensity|strength of the light whose periodicity detected by the light intensity detection part 12 is lost.

The wave height can be calculated by the following formula.

Wave height = Received light intensity (tp) (mV) - Received light intensity (tb) (mV)

Here, the light reception intensity tp (mV) represents the peak top light reception intensity of the light reception intensity change caused by the periodic change of the illumination light in a predetermined period. In the case of a change in light reception intensity of 100 ms, Fig. 2(A) corresponds to the light reception intensity of the peak top. The light reception intensity tb (mV) represents the light reception intensity at the bottom of the periodic light reception intensity change in a predetermined period. In the case of a change in light reception intensity of 100 ms, (B) of FIG. 2 corresponds to the light reception intensity of the bottom. Accordingly, the wave height at a change in light reception intensity of 100 ms is (C) in FIG. 2 . In addition, (tp) represents the time point at which the change in received light intensity becomes the peak top. (tb) represents the point at which the bottom of the change in received light intensity is reached. Moreover, although the predetermined period was 100 ms in embodiment, it is not limited to this, It is good also as about 100 ms vicinity or another period.

In the case of using indoor light, etc., when there are multiple light sources, a waveform with a shoulder may be formed due to the difference in emission intensity of the light sources, etc., but also in that case, as described above, the peak at the time of measurement You can use a top and a peak bottom.

In addition, in the calculation of the periodic change amount, the wave height may be analyzed as the difference between the average value and the peak top, or the difference between the average value and the peak bottom, that is, the half value.

The control unit 13 calculates the blood pressure based on the wave height (the difference between the maximum value and the minimum value of the light reception intensity of the light having lost its periodicity in a predetermined period). In this calculation method, for example, as shown in FIG. 5 , a correlation between wave height and blood pressure is created for a plurality of persons, data using this as a calibration curve is stored in the HDD 135, and the control unit 13 is configured to: The blood pressure corresponding to the wave height is calculated from the data. The wave height may be correlated with blood pressure as the difference between the average value and the peak top of the light reception intensity in a predetermined period, or the difference between the average value and the peak bottom, that is, the half value.

In addition, in the embodiment, the irradiation unit, the light-receiving intensity detection unit, and the control unit are configured as an integrated device, but the present invention is not limited thereto. The control unit may be provided in a server device or the like connected to the user device through a network using lighting (LED, etc.) or a sensor (CMOS, etc.) provided in the device.

The blood pressure measuring device of the embodiment comprises: an irradiator for irradiating light with periodicity to a subject having a first layer on the surface and a second layer absorbing light more than the first layer below the first layer; Light having periodicity passes through the first layer and the second layer and becomes light with loss of periodicity and is disposed at a detected distance, and includes a light intensity detection unit for detecting the intensity of light with loss of periodicity emitted from the subject. communicatively connected to the user device. The blood pressure measuring apparatus includes a control unit that obtains a wave height from the intensity of light having lost periodicity transmitted from the user device, and calculates blood pressure in the subject from the wave height. Incidentally, as for the content of specific processing, since it is the same as that of the blood pressure measuring apparatus of the said embodiment, description is abbreviate|omitted.

Fig. 8 is a diagram showing the configuration of a blood pressure measuring device according to another embodiment.

The blood pressure measuring system of the embodiment includes a user device 300 for measuring light intensity, and a blood pressure measuring device 200 for calculating blood pressure from the light intensity. The user device 300 and the blood pressure measuring device 200 are network-connected via a wireless or wired communication network N.

The blood pressure measuring device 200 is a device for performing predetermined processing based on the light intensity transmitted from the user device 300 and calculating the blood pressure, specifically, a personal computer, the number of devices, and data to be transmitted and received. Depending on the amount, the server device is used appropriately.

The user device 300 is a device possessed by a user, and may be a single device or may be mounted on a mobile phone, a wrist watch, or the like.

The user device 300 includes an irradiator 31 for irradiating light with periodicity to a subject having a first layer on the surface and a second layer that absorbs light more than the first layer below the first layer; The excitation light passes through the first and second layers and includes a light intensity detection unit 32 and a communication unit 33 for detecting the intensity of the light having lost its periodicity. The communication unit 33 transmits the intensity of light having lost the periodicity detected by the light intensity detection unit 32 . About the operation|movement and function of the irradiation part 31 and the light intensity detection part 32, it is the same as that of the said embodiment.

The blood pressure measuring device 200 includes a communication unit 24 and a control unit 23 . The communication unit 24 receives the intensity of light that has lost the periodicity transmitted from the communication unit 33 via the wired or wireless network N, and transmits it to the control unit 23 . About the operation and function of the control part 23, it is the same as that of the control part 13 of the said embodiment.

Also, in the present embodiment, the intensity of light having lost periodicity is transmitted from the user device 300 to the blood pressure measuring device 200 via the network N. However, the present invention is not limited thereto. The blood pressure measuring device 200 may be directly connected without interposing the network N and transmit the light intensity by means such as wired communication or wireless communication.

Next, the blood pressure measuring method of the embodiment will be described. Fig. 9 is a flowchart of the blood pressure measuring method according to the embodiment.

In the blood pressure measuring method of the embodiment, the irradiation unit applies light having periodicity to a subject having a first layer on the surface and a second layer that absorbs light more than the first layer below the first layer at a predetermined irradiation position. is irradiated (step 101), and the light intensity detecting unit emits light from the subject at a position where the light having periodicity passes through the first and second layers from the irradiation position and becomes light having lost the periodicity and is detected. The intensity of the light having lost the periodicity is detected (step 102), the control unit obtains the wave height from the intensity of the light having lost the periodicity (step 103), and the blood pressure is obtained from the wave height (step 104). In addition, about the content of a specific process, since it is the same as that of the blood pressure measuring apparatus of the said embodiment, description is abbreviate|omitted.

Next, the blood pressure measurement program of the embodiment will be described.

The device comprises: an irradiating unit irradiating light having periodicity to a subject having a first layer on its surface and a second layer absorbing light more than the first layer below the first layer; Communication to a user device including a light intensity detector for detecting the intensity of light having lost periodicity, which has passed through the first and second layers, is disposed at a position to be detected as light with loss of periodicity, and which is emitted from a subject. possible to connect

The blood pressure measurement program of the embodiment causes the device computer to execute a process of obtaining a wave height from the intensity of light transmitted from the user device having lost periodicity, and obtaining a blood pressure from the wave height. In addition, about the content of a specific process, since it is the same as that of the said embodiment, description is abbreviate|omitted.

As mentioned above, although embodiment was described, this embodiment is shown as an example, and limiting the scope of the invention is not intended. This novel embodiment can be implemented in other various forms, and various abbreviation|omission, substitution, and change can be performed in the range which does not deviate from the summary of invention. This embodiment and its modifications are included in the scope and gist of the invention, and the invention described in the claims and their equivalents.

100: blood pressure measuring device
11: Investigation Department
12: light reception intensity detection unit
13: control

Claims (7)

A blood pressure measuring device comprising:
an irradiation unit for irradiating light having periodicity to a subject having a first layer on its surface and a second layer absorbing light more than the first layer under the first layer;
From the irradiation unit, the light having the periodicity passes through the first layer and the second layer, becomes light having lost its periodicity, is disposed at a detected distance, and emitted from the subject. a light intensity detector for detecting the intensity; and
A control unit for calculating the blood pressure in the subject from the intensity of the light having lost the periodicity
A blood pressure measuring device comprising a. The blood pressure measuring device according to claim 1, wherein the distance at which the light having the periodicity becomes the light having lost the periodicity and is detected is a distance at which a light reception intensity of 1/20 or more is obtained with respect to the intensity of the incident light from the irradiation unit. The blood pressure measuring apparatus according to claim 1, wherein the distance at which the light having periodicity is detected as the light having lost the periodicity is a distance at which the period of the light from the irradiation unit cannot be confirmed by FFT analysis. The blood pressure measuring device according to claim 1, wherein the control unit calculates the blood pressure of the subject from a difference between a maximum value and a minimum value of the intensity of light having lost the periodicity in a predetermined period. The blood pressure measuring apparatus according to claim 4, wherein the predetermined period is approximately 100 ms. A blood pressure measuring device comprising:
an irradiating unit irradiating light having a periodicity to a subject having a first layer on its surface and a second layer absorbing light more than the first layer under the first layer; , passing through the first layer and the second layer, being disposed at a distance to be detected as light having lost its periodicity, and comprising a light intensity detection unit configured to detect the intensity of light that has lost its periodicity emitted from the subject. A blood pressure measuring device communicatively connected to a user device, comprising:
and a controller configured to calculate the blood pressure in the subject from the intensity of the light that has lost the periodicity transmitted from the user device. A blood pressure measurement method comprising:
irradiating light having a periodicity to a subject having a first layer on its surface and a second layer absorbing more light than the first layer under the first layer;
The intensity of the light having lost the periodicity emitted from the subject at a position where the light having the periodicity from the irradiation position passes through the first layer and the second layer and becomes light losing the periodicity and is detected. detecting; and
calculating blood pressure in the subject from the intensity of the light having lost the periodicity
A blood pressure measurement method comprising:

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